Re: [Qemu-devel] [PATCH v6 2/2] block: Support GlusterFS as a QEMU block backend

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

On Thu, Sep 06, 2012 at 11:29:36AM +0300, Avi Kivity wrote:
> On 08/14/2012 12:58 PM, Kevin Wolf wrote:
> > 
> >> While we are at this, let me bring out another issue. Gluster supports 3
> >> transport types:
> >> 
> >> - socket in which case the server will be hostname, ipv4 or ipv4 address.
> >> - rdma in which case server will be interpreted similar to socket.
> >> - unix in which case server will be a path to unix domain socket and this
> >>   will look like any other filesystem path. (Eg. /tmp/glusterd.socket)
> >> 
> >> I don't think we can fit 'unix' within the standard URI scheme (RFC 3986)
> >> easily, but I am planning to specify the 'unix' transport as below:
> >> 
> >> gluster://[/path/to/unix/domain/socket]/volname/image?transport=unix
> >> 
> >> i,e., I am asking the user to put the unix domain socket path within
> >> square brackets when transport type is unix.
> >> 
> >> Do you think this is fine ?
> > 
> > Never saw something like this before, but it does seem reasonable to me.
> > Excludes ] from the valid characters in the file name of the socket, but
> > that shouldn't be a problem in practice.
> 
> Bikeshedding, but I prefer
> 
>   gluster:///path/to/unix/domain/socket:/volname/image?transport=unix

So if the unix domain socket is /tmp/glusterd.socket, then this would look like:

gluster:///tmp/glusterd.socket:/volname/image?transport=unix.

So you are saying : will the separator b/n the unix domain socket path
and rest of the URI components.

Unless you or others strongly feel about this, I would like to go with
[ ] based spec, which I feel is less prone to errors like missing a colon
by mistake :)

> 
> as being more similar to file://, or even
> 
>   gluster:///path/to/unix/domain/socket/volname/image?transport=unix
> 
> with the last two components implied to be part of the payload, not the
> path.

Note that image is a file path by itself like /dir1/a.img. So I guess it
becomes difficult to figure out where the unix domain socket path ends
and rest of the URI components begin w/o a separator in between.

Regards,
Bharata.